The present invention relates to portable data processors, and specifically to programmable data processors for performing a variety of applications with a corresponding variety of attachable appliances.
Many portable consumer and professional appliances employ both a processor and memory of large capacity, for instance digital cameras, MP3 players, digital voice recorders, PDAs (personal digital assistants), etc. Often the cost of the memory and processor represents a substantial percentage of the overall cost of the appliance. Thus a user who buys a variety of such appliances will pay several times for a multiplicity of similar hardware components.
Some vendors have introduced add-on modules that add functionality to their core product. For example, there are commercial products that allow attaching a digital camera accessory or voice recorder accessory to a personal data assistant (PDA). The user of the PDA then can take photographs with his new accessory, but must also carry his PDA when he needs to take photos even if he does not need the PDA functionality on that occasion.
There are commercial detachable memory modules of various forms, features and capacities. Some can be connected to a variety of devices and appliances, e.g. the same Compact Flash card can be used with a personal computer, a PDA, a GPS navigator, a digital camera or an MP3 player. Most of these modules have nonvolatile memories, and some of these modules also include data processors for managing the efficiency and/or security of the access to the memory. This processing power, however, is limited in the prior art to the functionality of the memory module alone. Also, the role of the detachable memory module is to carry data, while the device or appliance which accepts such a detachable memory module has its own data processor and operates from program code recorded in its own, fixed memory.
Thus, the prior art has not exploited the potential of the storage capacity and processing power of detachable modules for operating a variety of devices and appliances.